1. Field of the Invention
This invention relates to an agricultural implement, and more particularly to a hinge structure which permits a wing structure to float relative to a main frame of the implement when in an working position but adjusts to a different mode to allow the wing to be folded upward to a transport condition.
2. Description of the Prior Art
Many agricultural implements, including earth tillage equipment, seeders, and crop harvesting equipment, are made up of a number of sections arranged end to end in the transverse direction so as to provide an wide implement capable of covering a wide swath on each pass. Usually the implement includes a main or central frame section mounted on its own wheel structure or other ground engaging means, and the other sections, which may be disposed at one or both ends of the central frame structure, are in the form of wings which may be folded upward to make the overall width less and thereby place the implement in a travel condition. When the outer or wing sections are in their lowered or work position, they are usually carried on their own wheels or other ground engaging means. In some known implements the pivot connection which is provided between the frame of the wing and the main frame is formed in a fashion to form a rigid connection between the main and wing frames when the wings are lowered to their operative position, but such a structure has the disadvantage of the ground working parts of the implement varying in their relation to the ground surface as the implement passes over uneven terrain. Such a deficiency in the implement increases, of course, as the width of the implement or the unevenness of the ground increases. Thus there have been designed pivoting connections between the main frame and the frames of the wings for allowing the wings to pivot relative to the main frame. Such an arrangement does not necessarily accommodate ground unevenness well because the wings only pivot about a single axis at their inner ends, and the relative motion enjoyed by the wings is not a true floating action. Although designs have been proposed to allow a more universal connection between implement wings and the main frame and thereby provide for a truer floating action of the wings, the designs have been generally complex and cumbersome. Most of the commercially adopted hinging mechanisms, whether of the type which allow relative movement between the wings and the main frame of the implement, and whether the permitted movement is simple that of allowing the wing to pivot relative to the main frame, have added significantly to the cost of the implement and/or require additional manipulation by the operator in the raising and lowering process. If provision is made to accommodate some form of lost motion in achieving a floating action of the wing, some form of mechanism must also be present to override the lost motion during raising and lowering of the wing, and generally, such mechanisms require separate inconvenient operation by the user of the implement or the addition many extra parts to bring about a more automatic response to the raising of the wing.